345 lines
14 KiB
Python
345 lines
14 KiB
Python
"""Python STIX2 TAXIICollection Source/Sink"""
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from requests.exceptions import HTTPError
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from stix2 import v20, v21
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from stix2.base import _STIXBase
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from stix2.datastore import (
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DataSink, DataSource, DataSourceError, DataStoreMixin,
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)
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from stix2.datastore.filters import Filter, FilterSet, apply_common_filters
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from stix2.parsing import parse
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from stix2.utils import deduplicate
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try:
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from taxii2client.exceptions import ValidationError
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_taxii2_client = True
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except ImportError:
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_taxii2_client = False
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TAXII_FILTERS = ['added_after', 'id', 'type', 'version']
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class TAXIICollectionStore(DataStoreMixin):
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"""Provides an interface to a local/remote TAXII Collection
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of STIX data. TAXIICollectionStore is a wrapper
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around a paired TAXIICollectionSink and TAXIICollectionSource.
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Args:
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collection (taxii2.Collection): TAXII Collection instance
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allow_custom (bool): whether to allow custom STIX content to be
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pushed/retrieved. Defaults to True for TAXIICollectionSource
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side(retrieving data) and False for TAXIICollectionSink
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side(pushing data). However, when parameter is supplied, it will
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be applied to both TAXIICollectionSource/Sink.
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"""
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def __init__(self, collection, allow_custom=None):
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if allow_custom is None:
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allow_custom_source = True
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allow_custom_sink = False
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else:
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allow_custom_sink = allow_custom_source = allow_custom
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super(TAXIICollectionStore, self).__init__(
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source=TAXIICollectionSource(collection, allow_custom=allow_custom_source),
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sink=TAXIICollectionSink(collection, allow_custom=allow_custom_sink),
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)
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class TAXIICollectionSink(DataSink):
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"""Provides an interface for pushing STIX objects to a local/remote
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TAXII Collection endpoint.
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Args:
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collection (taxii2.Collection): TAXII2 Collection instance
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allow_custom (bool): Whether to allow custom STIX content to be
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added to the TAXIICollectionSink. Default: False
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"""
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def __init__(self, collection, allow_custom=False):
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super(TAXIICollectionSink, self).__init__()
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if not _taxii2_client:
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raise ImportError("taxii2client library is required for usage of TAXIICollectionSink")
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try:
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if collection.can_write:
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self.collection = collection
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else:
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raise DataSourceError(
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"The TAXII Collection object provided does not have write access"
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" to the underlying linked Collection resource",
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)
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except (HTTPError, ValidationError) as e:
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raise DataSourceError(
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"The underlying TAXII Collection resource defined in the supplied TAXII"
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" Collection object provided could not be reached. Receved error:", e,
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)
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self.allow_custom = allow_custom
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def add(self, stix_data, version=None):
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"""Add/push STIX content to TAXII Collection endpoint
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Args:
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stix_data (STIX object OR dict OR str OR list): valid STIX2
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content in a STIX object (or Bundle), STIX object dict (or
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Bundle dict), or a STIX2 json encoded string, or list of
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any of the following.
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version (str): If present, it forces the parser to use the version
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provided. Otherwise, the library will make the best effort based
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on checking the "spec_version" property.
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"""
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if isinstance(stix_data, _STIXBase):
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# adding python STIX object
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if stix_data['type'] == 'bundle':
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bundle = stix_data.serialize(encoding='utf-8', ensure_ascii=False)
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elif 'spec_version' in stix_data:
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# If the spec_version is present, use new Bundle object...
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bundle = v21.Bundle(stix_data, allow_custom=self.allow_custom).serialize(encoding='utf-8', ensure_ascii=False)
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else:
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bundle = v20.Bundle(stix_data, allow_custom=self.allow_custom).serialize(encoding='utf-8', ensure_ascii=False)
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elif isinstance(stix_data, dict):
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# adding python dict (of either Bundle or STIX obj)
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if stix_data['type'] == 'bundle':
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bundle = parse(stix_data, allow_custom=self.allow_custom, version=version).serialize(encoding='utf-8', ensure_ascii=False)
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elif 'spec_version' in stix_data:
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# If the spec_version is present, use new Bundle object...
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bundle = v21.Bundle(stix_data, allow_custom=self.allow_custom).serialize(encoding='utf-8', ensure_ascii=False)
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else:
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bundle = v20.Bundle(stix_data, allow_custom=self.allow_custom).serialize(encoding='utf-8', ensure_ascii=False)
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elif isinstance(stix_data, list):
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# adding list of something - recurse on each
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for obj in stix_data:
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self.add(obj, version=version)
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return
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elif isinstance(stix_data, str):
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# adding json encoded string of STIX content
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stix_data = parse(stix_data, allow_custom=self.allow_custom, version=version)
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if stix_data['type'] == 'bundle':
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bundle = stix_data.serialize(encoding='utf-8', ensure_ascii=False)
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elif 'spec_version' in stix_data:
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# If the spec_version is present, use new Bundle object...
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bundle = v21.Bundle(stix_data, allow_custom=self.allow_custom).serialize(encoding='utf-8', ensure_ascii=False)
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else:
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bundle = v20.Bundle(stix_data, allow_custom=self.allow_custom).serialize(encoding='utf-8', ensure_ascii=False)
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else:
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raise TypeError("stix_data must be as STIX object(or list of),json formatted STIX (or list of), or a json formatted STIX bundle")
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self.collection.add_objects(bundle)
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class TAXIICollectionSource(DataSource):
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"""Provides an interface for searching/retrieving STIX objects
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from a local/remote TAXII Collection endpoint.
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Args:
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collection (taxii2.Collection): TAXII Collection instance
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allow_custom (bool): Whether to allow custom STIX content to be
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added to the FileSystemSink. Default: True
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"""
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def __init__(self, collection, allow_custom=True):
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super(TAXIICollectionSource, self).__init__()
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if not _taxii2_client:
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raise ImportError("taxii2client library is required for usage of TAXIICollectionSource")
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try:
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if collection.can_read:
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self.collection = collection
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else:
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raise DataSourceError(
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"The TAXII Collection object provided does not have read access"
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" to the underlying linked Collection resource",
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)
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except (HTTPError, ValidationError) as e:
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raise DataSourceError(
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"The underlying TAXII Collection resource defined in the supplied TAXII"
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" Collection object provided could not be reached. Recieved error:", e,
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)
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self.allow_custom = allow_custom
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def get(self, stix_id, version=None, _composite_filters=None):
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"""Retrieve STIX object from local/remote STIX Collection
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endpoint.
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Args:
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stix_id (str): The STIX ID of the STIX object to be retrieved.
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version (str): If present, it forces the parser to use the version
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provided. Otherwise, the library will make the best effort based
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on checking the "spec_version" property.
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_composite_filters (FilterSet): collection of filters passed from
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the parent CompositeDataSource, not user supplied
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Returns:
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(STIX object): STIX object that has the supplied STIX ID.
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The STIX object is received from TAXII has dict, parsed into
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a python STIX object and then returned
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"""
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# combine all query filters
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query = FilterSet()
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if self.filters:
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query.add(self.filters)
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if _composite_filters:
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query.add(_composite_filters)
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# don't extract TAXII filters from query (to send to TAXII endpoint)
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# as directly retrieving a STIX object by ID
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try:
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stix_objs = self.collection.get_object(stix_id)['objects']
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stix_obj = list(apply_common_filters(stix_objs, query))
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except HTTPError as e:
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if e.response.status_code == 404:
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# if resource not found or access is denied from TAXII server,
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# return None
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stix_obj = []
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else:
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raise DataSourceError("TAXII Collection resource returned error", e)
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if len(stix_obj):
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stix_obj = parse(stix_obj[0], allow_custom=self.allow_custom, version=version)
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if stix_obj['id'] != stix_id:
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# check - was added to handle erroneous TAXII servers
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stix_obj = None
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else:
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stix_obj = None
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return stix_obj
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def all_versions(self, stix_id, version=None, _composite_filters=None):
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"""Retrieve STIX object from local/remote TAXII Collection
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endpoint, all versions of it
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Args:
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stix_id (str): The STIX ID of the STIX objects to be retrieved.
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version (str): If present, it forces the parser to use the version
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provided. Otherwise, the library will make the best effort based
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on checking the "spec_version" property.
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_composite_filters (FilterSet): collection of filters passed from the parent
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CompositeDataSource, not user supplied
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Returns:
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(see query() as all_versions() is just a wrapper)
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"""
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# make query in TAXII query format since 'id' is TAXII field
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query = [
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Filter('id', '=', stix_id),
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Filter('version', '=', 'all'),
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]
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all_data = self.query(query=query, _composite_filters=_composite_filters)
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# parse STIX objects from TAXII returned json
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all_data = [parse(stix_obj, allow_custom=self.allow_custom, version=version) for stix_obj in all_data]
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# check - was added to handle erroneous TAXII servers
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all_data_clean = [stix_obj for stix_obj in all_data if stix_obj['id'] == stix_id]
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return all_data_clean
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def query(self, query=None, version=None, _composite_filters=None):
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"""Search and retreive STIX objects based on the complete query
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A "complete query" includes the filters from the query, the filters
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attached to MemorySource, and any filters passed from a
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CompositeDataSource (i.e. _composite_filters)
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Args:
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query (list): list of filters to search on
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version (str): If present, it forces the parser to use the version
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provided. Otherwise, the library will make the best effort based
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on checking the "spec_version" property.
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_composite_filters (FilterSet): collection of filters passed from
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the CompositeDataSource, not user supplied
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Returns:
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(list): list of STIX objects that matches the supplied
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query. The STIX objects are received from TAXII as dicts,
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parsed into python STIX objects and then returned.
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"""
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query = FilterSet(query)
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# combine all query filters
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if self.filters:
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query.add(self.filters)
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if _composite_filters:
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query.add(_composite_filters)
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# parse taxii query params (that can be applied remotely)
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taxii_filters = self._parse_taxii_filters(query)
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# taxii2client requires query params as keywords
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taxii_filters_dict = dict((f.property, f.value) for f in taxii_filters)
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# query TAXII collection
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try:
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all_data = self.collection.get_objects(**taxii_filters_dict).get('objects', [])
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# deduplicate data (before filtering as reduces wasted filtering)
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all_data = deduplicate(all_data)
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# apply local (CompositeDataSource, TAXIICollectionSource and query) filters
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query.remove(taxii_filters)
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all_data = list(apply_common_filters(all_data, query))
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except HTTPError as e:
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# if resources not found or access is denied from TAXII server, return empty list
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if e.response.status_code == 404:
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raise DataSourceError(
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"The requested STIX objects for the TAXII Collection resource defined in"
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" the supplied TAXII Collection object are either not found or access is"
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" denied. Received error: ", e,
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)
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# parse python STIX objects from the STIX object dicts
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stix_objs = [parse(stix_obj_dict, allow_custom=self.allow_custom, version=version) for stix_obj_dict in all_data]
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return stix_objs
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def _parse_taxii_filters(self, query):
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"""Parse out TAXII filters that the TAXII server can filter on
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Does not put in TAXII spec format as the TAXII2Client (that we use)
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does this for us.
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Note:
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Currently, the TAXII2Client can handle TAXII filters where the
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filter value is list, as both a comma-seperated string or python
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list.
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For instance - "?match[type]=indicator,sighting" can be in a
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filter in any of these formats:
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Filter("type", "<any op>", "indicator,sighting")
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Filter("type", "<any op>", ["indicator", "sighting"])
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Args:
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query (list): list of filters to extract which ones are TAXII
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specific.
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Returns:
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A list of TAXII filters that meet the TAXII filtering parameters.
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"""
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taxii_filters = []
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for filter_ in query:
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if filter_.property in TAXII_FILTERS:
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taxii_filters.append(filter_)
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return taxii_filters
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